The investigators will study and describe the longitudinal patterns of behavior of 248 male chronic opioid users in San Antonio. The subjects were hospitalized for treatment of opioid dependence during the years 1964 through 1967. Longitudinal data collecting began in 1966 and continues in 1977. Data are collected by periodic interviews with subjects, and by review of records about subjects in law enforcement, correctional, and treatment agencies. In addition data are collected about brothers who did not use opioid drugs daily, and about community conditions affecting opioid use. Subjects are male and predominantly Mexican-American. They began opioid use at the median age of 17; in 1977 the group has a median age of 39. The study will produce statistical description of the chronological life experiences of subjects, of the relation of background predictors to long-term outcomes, and of the consequences of multiple treatment and correctional interactions.